This is an ancillary study to be conducted in conjunction with a multicenter trial of mild intraoperative hypothermia on neurological outcome (IHAST), already funded by NINDS (NS38554), which is currently in progress. This will be a multicenter, prospective, partially blinded clinical study of the rate of recovery of cognitive function in patients who have undergone craniotomy for clipping of intracranial aneurysms. Specific aim of this investigation is to study the effects of intraoperative hypothermia and anatomical location of aneurysm on the rate of recovery of neurocognitive function. Patients in IHAST are randomized to normothermic (36.5 degrees C) and hypothermic (33 degrees C) groups based on the core body temperature at the time of aneurysm clip application. Patients, neurosurgeons, neurological examiners and study coordinators are blinded to the group assignments. Long term outcome is assessed 3 months after surgery, which is the end point of current study. We propose to do two additional tests of neuropsychological function and prolong the period of follow up to 1 year in a subset of English speaking patients, enrolled in IHAST. Patients will be recruited for this study, at the time of last visit for IHAST, therefore this study can not possibly interfere with IHAST protocol. In consenting patients, an assessment of neuropsychological function will be done at 3, 6 and 12 months after surgery. Neuropsychologists, administering/scoring these tests will be blinded to the group assignment (hypothermia/normothermia) and location of the aneurysm. The effect of hypothermia and location of aneurysm (anterior communicating, anterior cerebral, middle cerebral, posterior communicating and basilar arteries) on performance and rate of recovery of neuropsychological function will be studied by appropriate statistical analyses. We hypothesize that intraoperative hypothermia will result in better preservation of neurocognitive function and aneurysm location will have significant effect on rate of recovery of cognitive function. Information gained from this investigation will be important in giving a prognosis for returning back to work as well as planning rehabilitation of patients suffering from aneurysmal SAH in future.